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The scene file You also need both these GIF files: Colour map (20 KB) * Height field (215 kB) * * Right click the links (long click on the Mac) to save the files rather than displaying them in the browser.	Raytraced sample image Isn't this OTT for just stones? Design notes Back to Chris' Ray Tracing Page

Sample Image

(© Chris Bartlett 1995)

This technique also provides a good profiled corner which can be important where you are either looking straight at the corner, or at an object just around the corner. Many techniques (e.g use of surface normal) can leave a straight edge which betrays the computer generated origin of the image.

The original stonework pattern was created in black and white using a standard drawing application.

By copying a block from the left hand side of the image and pasting on the right the two sides were merged together so that the finished panels would join seamlesly. The same process was performed from top to bottom to enable the pattern to merge on all edges.

Two copies were then taken and colourised. The first was colourised with 16 colours to represent the colours of the stones in the wall. The second with 256 colours to form a height field representing the profile of the stonework.

The colour map was simply coloured using the fill area (paint pot) feature of a paint program.

The height_field gif was worked on with a height field utility program to selectively lower parts of the stone surfaces.